1. Technical Field
The present invention relates to optical package structures, and more particularly to a micro optical package structure having filtration layers and a method for making the micro optical package structure.
2. Description of Related Art
Nowadays, electronic technology changes with each passing day, in which optical sensing particularly has extensive applications for, such as, fingerprint or iris recognition, and ambient or incident light sensing.
FIG. 1 shows a conventional optical package structure 1, which comprises a substrate 2, a light-emitting chip 3, a light-receiving chip 4, and a package shell 5. The light-emitting chip 3 and the light-receiving chip 4 are deposited on the substrate 2. The package shell 5 covers the light-emitting chip 3 and the light-receiving chip 4, and is connected with the substrate 2. For preventing interference acting on the light-receiving chip 4 caused by scattering or diffraction of the light emitted by the light-emitting chip 3, a partition 6 is provided in the package shell 5 for separating the light-emitting chip 3 from the light-receiving chip 4. Thereby, the light emitted by the light-emitting chip 3 is blocked by the partition 6 and prevented from going to the light-receiving chip 4 through scattering or diffraction, so as to improve the sensitivity of the light-receiving chip 4. While such an optical package structure 1 does have the light-emitting chip 3 and the light-receiving chip 4 separated, the existence of the package shell 5 containing the partition 6 is necessary, so of the optical package structure 1 is limited and this is against the trend of modern optical packaging toward compactness and microminiaturization.
In addition to scattering or diffraction of the light emitted by the light-emitting chip 3, another factor degrading the optical sensitivity of the light-receiving chip 4 is visible lights of different wavelengths (380 nm to 780 nm). As shown in FIG. 2, in another conventional optical package structure 1′, for preventing visible lights from degrading the sensitivity, filters 9 are installed over the light-emitting aperture 7 and the light-receiving aperture 8 of the package shell 5, so as to filter out visible lights of different wavelengths and improve the recognition of the light-receiving chip 4 of the optical package structure 1′. However, the addition of the filter 9 is not only adverse to microminiaturization of the optical package structure 1′, but also requires additional processing steps and increased material costs, thus being disadvantageous.
To sum up, the conventional optical package structures 1, 1′ are imperfect and need to be improved.